XO and VSOP are grades of cognac, a type of brandy made from distilled wine.

XO, which stands for "extra old," is the highest-grade cognac and requires that all the cognac in the blend is aged for at least 10 years in oak casks. The resulting cognac is typically smooth, full-bodied, and complex with flavors of dried fruit, vanilla, and spice.

VSOP, which stands for "very superior old pale," is a grade below XO and requires that the cognac is aged for at least 4 years in oak casks. This cognac is also smooth and complex, but with a milder flavor profile than XO, featuring notes of fruit, floral, and oak.

In summary, while both XO and VSOP cognacs are of high quality, XO is generally considered to be more refined and complex due to its longer aging process.